I also do not think that there is any discrepancy between a Dom and a caring man. Dominant does not mean uncaring or inconsiderate it just means someone who controls certain aspects of your life. This can be done in a caring way.

You also need to explore the concepts of aftercare. Make sure that after every session when you are both 'in character' (i.e. him being a cruel dominant and you being whatever form of sub you are) that you spend sometime coming down from it. You will both need hugs, gentle stroking, possibly a good cry.

I remember when I used to claim to be a Dom (well, I used to be a switch so I did occasionally Dom sub women). I say claim because I was singularly bad at it - just could not get into the mindset of 'if I hurt her she likes it'. Maybe more practise would have helped, maybe talking with other Doms, maybe having a more experienced sub for a longer period of time. As it was I decided to ditch the switch label as I realised I was more sub than Dom. I was great at thinking up ideas for what to do to subs (which is why many Mistresses like me and some subs I know hate me... ) but useless at stepping up to the plate and swinging the whip myself.

Perhaps getting him to talk through his feelings with someone - you, a friend, another Dom - may help?